Egypt's interim interior minister has pledged that protests calling for the reinstatement of ousted president Mohamed Morsi would be dispersed "soon".
Speaking at a news conference on Saturday, Mohamed Ibrahim said security forces would act "in a legal fashion" to disperse the demonstrations "as soon as possible".
He said security forces would act to ensure "the minimum losses possible".
Ibrahim insisted that security forces wanted to "prevent bloodshed," and made reference to complaints he said had been made by residents of the areas where Morsi supporters are demonstrating.
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"We hope that [the protesters] come to their sense and that they put an end to these protests in order to prevent bloodshed," he added.
He also denied police had opened fire, accusing the Muslim Brotherhood of exaggerating for political ends.
The country's National Defence Council met late on Saturday night to discuss the security situation.
Conflicting reports have emerged over the number of people killed in overnight clashes between those protesting against military rule and security forces in the Egyptian capital.
Ahmed Aref, the Muslim Brotherhood spokesperson, said 66 people were killed, another 61 are "clinically dead", and a further 4,500 people were injured, 700 of which were injured by live bullets.
The health ministry, meanwhile, has put the figure at 80 killed so far, based on the number of bodies received at the morgue. It said 792 people had been injured in the clashes.
Al Jazeera's Hoda Abdel Hamid, reporting from Cairo, said: "The country is even more divided than before, and showing no signs of understanding the other side," our correspondent said.
Supporters and opponents of Morsi staged mass rival rallies across the country on Friday, bringing hundreds of thousands into the streets.
Running battles broke out at dawn, with police firing tear gas at stone-throwing protesters, the official MENA news agency said.
Egypt's interior ministry defended the actions of security forces, with spokesman General Hany Abdel Latif saying police "did not use more than tear gas".
[Morsi stands accused of the] premeditated murder of some prisoners, officers and soldiers.
He accused pro-Morsi protesters of firing on the security forces, wounding 14 policemen, including two who were in critical condition after being shot in the head.
Al Jazeera's Abdel Hamid said there was no clear information on who started the overnight violence, with each side accusing the other of starting the clashes.
"After the minister of interior spoke, both sides decided they will believe the versions they want to believe, so at the end of the day the full picture will never really emerge of who started shooting on who."
If the death toll of 120 is confirmed it would be the deadliest incident since Morsi was deposed by the army more than three weeks ago.
On July 8, 53 people, mostly Morsi supporters, died when armed men opened fire close to a Republican Guard compound in the area.
The prosecutor-general's office announced on Saturday that it would launch an investigation into the violence.
Clashes in Alexandria
Thousands of supporters and opponents of the army's removal of Morsi also took to the streets of the Mediterranean city of Alexandria on Friday, sparking fierce clashes that killed seven people and wounded 194.
The violence came after the authorities charged Morsi with murder and formally remanded him in custody for 15 days. He had been held without charge since hours after his removal from power.
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Morsi stands accused of the "premeditated murder of some prisoners, officers and soldiers" when he broke out of prison during the 2011 uprising that toppled veteran strongman Hosni Mubarak, MENA said.
Gihad El-Haddad, the spokesperson for Morsi's Muslim Brotherhood told Al Jazeera late on Saturday night that his group was considering a proposal made by a group of Egyptian intellectuals and civil society activists to resolve the crisis, but that there was "no meeting ground" with the military.
"There is no meeting ground. This is a zero-sum equation. It's either us or them in the equation. It's either we fully reverse this military coup, and continue back into constitutional legitimacy, or we die trying and they continue building a new military tyrannical regime. Like we've seen. [...] This is the beginning of a new military [dictatorship] in Egypt, even if a few civilian faces are slapped on top of it," he said.
Source: Al Jazeera and agencies